Just keep your V8 and pay it off if not already paid for... and if you want a new one get it while you can. There will be nice pre-owned examples to find. And supercharge it while your at it! I would still like to buy a pristine low mileage e46 m3.
Now, if you are an I6 fan and love the bottom more than the top
this next car just may be the one for you. I can't think of a sweeter combo to get the manual transmission in: low end torque + manual + lsd. Hopefully it has a higher redline. Not sure how vtronic and the valvetrain play into that. I am sure lag will be mitigated as much as possible in this one. And think the engineering prowess BMW will be able to gloat because they were able to bring a 6 up to or exceed what the competition can do with an 8. It is kinda like the tiny yet massive engine and F1 going to 6 then 4 and the XJ220 with its savage turbo V6. BMW has already done the 8/10 quite well.
Or have both. I just hope the F8x has some lungs up top. No matter what and no matter how much this or that or comparison is done, the S65 is and always will be a mechanical masterpiece and symphony.
Like Scott said, not everyone is going to like the F8x. And I thought I read somewhere that the N54 was originally designed by the M division for use in future M cars or something like but they brought the 8 instead.
I do wish the F8x was a P derived design.